Pacquiao's Twitter followers recently voted Khan, 30, as the opponent they would like to see him fight next.
Khan beat fellow Briton Kell Brook, Australia's Jeff Horn and American Terence Crawford with 48% of the vote.
He said on Twitter: "Currently negotiating with Manny #teampacquiao. Coming soon. Watch this space!"
Six-weight world champion Pacquaio, who said his next fight will be in the United Arab Emirates, added: "My team and I are in negotiations with Amir Khan for our next fight. Further announcement coming soon."
